Pelvic insufficiency fracture after pelvic irradiation in uterine cervix cancer

Insights into pelvic insufficiency fracture following pelvic radiotherapy for cervical cancer: a comparative review

BACKGROUND

Radiotherapy (RT)-induced pelvic insufficiency fractures (PIF) are prevalent in patients with cervical cancer. Inconclusive studies on PIF after cervical irradiation create uncertainty. This review examined PIF after RT in cervical patients, including its pathobiology, likely locations of fractures, incidence, clinical symptoms, and predisposing factors. We further discussed study limitations and therapeutic possibilities of PIF.

METHODS

The following online resources were searched for relevant articles: Google Scholar and PubMed. The keywords 'pelvic insufficiency fractures', 'cervical carcinoma' and 'cervical cancer', as well as 'chemoradiotherapy', 'chemoradiation', and 'radiotherapy', were some of the terms that were used during the search.

RESULTS

Patients with PIF report pelvic pain after radiation treatment for cervical cancer; the incidence of PIF ranges from 1.7 to 45.2%. Evidence also supports that among all patients treated with pelvic radiation, those who experienced pelvic insufficiency fractures invariably had at least one sacral fracture, making it the most frequently fractured bone in the body. Menopausal status, weight, BMI, age, and treatments and diagnosis modalities can influence PIF during radiotherapy.

CONCLUSIONS

In conclusion, our comparative review of the literature highlights significant heterogeneity in various aspects of PIF following radiation for patients with cervical cancer. This diversity encompasses prevalence rates, associated risk factors, symptoms, severity, diagnosis methods, preventive interventions, and follow-up periods. Such diversity underscores the complexity of PIF in this population and emphasizes the critical need for further research to elucidate optimal management strategies and improve patient outcomes.

Pilot Study: Short Term Impact of Radiation Therapy on Bone Mineral Density and Bone Metabolism

Despite the risk of complications, high dose radiation therapy is increasingly utilized in the management of selected bone malignancies. In this study, we investigate the impact of moderate to high dose radiation (over 50 Gy) on bone metabolism and structure. Between 2015 and 2018, patients with a primary malignant bone tumor of the sacrum that were either treated with high dose definitive radiation only or a combination of moderate to high dose radiation and surgery were prospectively enrolled at a single institution. Quantitative CTs were performed before and after radiation to determine changes in volumetric bone mineral density (BMD) of the irradiated and non-irradiated spine. Bone histomorphometry was performed on biopsies of the irradiated sacrum and the non-irradiated iliac crest of surgical patients using a quadruple tetracycline labeling protocol. In total, 9 patients were enrolled. Two patients received radiation only (median dose 78.3 Gy) and 7 patients received a combination of preoperative radiation (median dose 50.4 Gy), followed by surgery. Volumetric BMD of the non-irradiated lumbar spine did not change significantly after radiation, while the BMD of the irradiated sacrum did (pre-radiation median: 108.0 mg/cm3 (IQR 91.8-167.1); post-radiation median: 75.3 mg/cm3 (IQR 57.1-110.2); p = 0.010). The cancellous bone of the non-irradiated iliac crest had a stable bone formation rate, while the irradiated sacrum showed a significant decrease in bone formation rate [pre-radiation median: 0.005 mm3/mm2/year (IQR 0.003-0.009), post-radiation median: 0.001 mm3/mm2/year (IQR 0.001-0.001); p = 0.043]. Similar effects were seen in the cancellous and endocortical envelopes. This pilot study shows a decrease of volumetric BMD and bone formation rate after high-dose radiation therapy. Further studies with larger cohorts and other endpoints are needed to get more insight into the effect of radiation on bone. Level of evidence: IV.

Pelvic insufficiency fractures and pelvic bone metastases after neoadjuvant (chemo)radiotherapy for rectal cancer

BACKGROUND

Pelvic insufficiency fractures (PIFs) are a late complication of radiotherapy for pelvic malignancies. We evaluated the incidence, radiologic findings, clinical course, and outcome of PIFs in patients treated with neoadjuvant (chemo)radiotherapy ((C)RT) for rectal cancer.

MATERIAL AND METHODS

Data of patients diagnosed with rectal cancer from a large teaching hospital treated from 2002 to 2012 were extracted from the Dutch Cancer Registry. All hospital records were reviewed for the diagnosis of PIFs or pelvic bone metastases. An expert radiologist reassessed all imaging procedures of the lower back, abdomen, and pelvis.

RESULTS

A total of 513 rectal cancer patients were identified of whom 300 patients (58.5%) were treated with neoadjuvant (C)RT (long- vs. short-course radiotherapy: 91 patients [17.7%] vs. 209 [40.7%], respectively). Twelve PIFs were diagnosed initially according to hospital records and imaging reports of all 513 patients. These 12 patients were treated with neoadjuvant (C)RT. After reassessment of all pelvic imaging procedures done in this patient group (432 patients (84.2%)), 20 additional PIFs were detected in patients treated with neoadjuvant (C)RT, resulting in a 10.7% PIF rate in irradiated patients. One PIF was detected in the group of patients not treated with neoadjuvant (C)RT for rectal cancer. This patient had palliative radiotherapy for prostate cancer and is left out of the analysis. Median follow-up time of 32 PIF patients was 49 months. Median time between start of neoadjuvant (C)RT and diagnosis of PIF was 17 months (IQR 9-28). Overall median survival for patients with PIF was 63.5 months (IQR 44-120).

CONCLUSION

PIFs are a relatively common late complication of neoadjuvant (C)RT for rectal cancer but are often missed or misdiagnosed as pelvic bone metastases. The differentiation of PIFs from pelvic bone metastases is important because of a different treatment and disease outcome.

Therapy-induced bone changes in oncology imaging with 18F-sodium fluoride (NaF) PET-CT

¹⁸F-Sodium fluoride (¹⁸F-NaF) is a PET tracer that is mostly used in the evaluation of bone metastasis in oncology cases. Recently, ¹⁸F-NaF PET/CT is gaining wide popularity owing to its higher sensitivity over the other conventional bone tracer with higher and rapid single-pass extraction, negligible plasma protein binding, rapid blood, and renal clearance. In the era of constant evolution of cancer therapy regimens, considerable bone health impact is seen in the form of avascular necrosis, insufficiency fractures, among others. A significant number of these therapy-induced changes show high bone turnover and thereby ¹⁸F-NaF accumulation, mimicking metastatic lesions. This article summarizes and illustrates the pattern and morphological features of ¹⁸F-NaF PET/CT findings in these changes in the context of clinical and therapeutic history.

Sacral Insufficiency Fracture after Radiotherapy for Cervical Cancer: Appearance and Dynamic Changes on 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

Objective

With the increasing application of radiotherapy for cervical cancer, the incidence of sacral insufficiency fracture (SIF) is increasing gradually. Incorrect or untimely treatment caused by misdiagnosis may lead to serious adverse clinical consequences. This study retrospectively analyzed SIF caused by radiotherapy regarding the appearance and dynamic changes in 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (18F-FDG) positive emission tomography (PET)/computed tomography (CT) images to improve the understanding of SIF.

Materials and Methods

We retrospectively examined cervical cancer patients who underwent pelvic radiotherapy and 18F-FDG PET/CT between January 2014 and January 2021. Comparative analysis of the imaging performance and follow-up data was conducted. In total, 38 patients with ages ranging from 28 to 81 years (mean age 59.2 ± 10.6 y, median age 56 y) participated in the study. The respective characteristics of the 38 patients were summarized, and diagnosis was confirmed by follow-up changes.

Results

Twenty-five (65.8%) of the 38 patients suffered from unilateral SIF, and 13 (34.2%) suffered from bilateral SIF. After receiving radiotherapy, SIF first appeared in 3–42 months (median, 13 months). The main 18F-FDG PET/CT manifestations of SIF were increased bone density (35/38, 92.1%), anterior sacral fracture line (28/38, 73.7%), and diffuse or linear uptake patterns parallel to the sacroiliac joint (37/38, 97.3%), with the maximum standard uptake value (SUVmax) ranging from 1.8 to 5.9 (average, 3.1). Follow-up lasted 3–59 months (mean, 14 months). The main changes in SIF were increases in the bone density and high-density range and decreases in the FDG uptake intensity and hypermetabolism range. Three patients had secondary sacral or sacroiliac joint infection (3/38, 7.9%), and 3 patients had secondary fracture and/or pelvic deformation (3/38, 7.9%).

Conclusions

18F-FDG PET/CT is an effective technique for diagnosing SIF. A small fracture line in the anterior sacrum and diffuse or linear areas of high density or metabolism parallel to the sacroiliac joint were the characteristic features of SIF. The main changes in SIF were increases in the bone density and high-density range and decreases in the FDG uptake intensity and hypermetabolism range.

Pelvic Insufficiency Fractures in Cervical Cancer After Radiation Therapy: A Meta-Analysis and Review

AIM

The aim of the study was to estimate the prevalence of pelvic insufficiency fractures (PIFs) after radiation therapy (RT) in patients with cervical cancer.

PATIENTS AND METHODS

A total of 3,633 patients from 15 cohort studies were included. Proportion meta-analysis was performed to estimate prevalence and subgroup analysis was performed according to imaging modalities for diagnosis of PIF. For continuous variables (age and length of follow-up), meta-regression analysis was performed.

RESULTS

Pooled prevalence estimate of PIF was 14% (95% CI=10-19). Incidence of PIF was higher in studies that used MRI as a diagnostic tool (17%, 95% CI=12-22) than non-MRI (8%, 95% CI=2-14). In meta-regression, we found a significant association of prevalence of PIF with age (p=0.021) but not with length of follow-up (p=0.118).

CONCLUSION

PIF after RT in patients with cervical cancer is not rare. Physicians need to pay attention to PIFs, especially in patients with high-risk factors for osteoporotic fracture.

An easy way to determine bone mineral density and predict pelvic insufficiency fractures in patients treated with radiotherapy for cervical cancer

Purpose

The aim of this study was to investigate whether bone mineral density (BMD) as measured in planning computed tomographies (CTs) by a new method is a risk factor for pelvic insufficiency fractures (PIF) after radio(chemo)therapy (R(C)T) for cervical cancer.

Methods

62 patients with cervical cancer who received definitive or adjuvant radio(chemo)therapy between 2013 and 2017 were reviewed. The PIF were detected on follow-up magntic resonance imaging (MRI). The MRI of the PIF patients was registered to the planning CT and the PIF contoured. On the contralateral side of the fracture, a mirrored structure of the fracture was generated (mPIF). For the whole sacral bone, three lumbar vertebrae, the first and second sacral vertebrae, and the PIF, we analyzed the BMD (mg/cm³), V50Gy, Dmean, and Dmax.

Results

Out of 62 patients, 6 (9.7%) had a fracture. Two out of the 6 patients had a bilateral fracture with only one of them being symptomatic. PIF patients showed a significantly lower BMD in the sacral and the lumbar vertebrae (p < 0.05). The BMD of the contoured PIF, however, when comparing to the mPIF, did not reach significance (p < 0.49). The difference of the V50Gy of the sacrum in the PIF group compared to the other (OTH) patients, i.e. those without PIF, did not reach significance.

Conclusion

The dose does not seem to have a relevant impact on the incidence of PIF in our patients. One of the predisposing factors for developing PIF after radiotherapy seems to be the low BMD. We presented an easy method to assess the BMD in planning CTs.

Pelvic fractures and changes in bone mineral density after radiotherapy for cervical, endometrial, and vaginal cancer: A prospective study of 239 women

BACKGROUND

Advances in radiotherapy (RT) have led to improved oncologic outcomes for women with gynecologic cancers; however, the long-term effects and survivorship implications need further evaluation. The purpose of this study was to determine the incidence of pelvic fractures and changes in bone mineral density (BMD) after pelvic RT.

METHODS

Two hundred thirty-nine women who had pelvic RT for cervical, endometrial, or vaginal cancer between 2008 and 2015 were prospectively studied. BMD scans and biomarkers of bone turnover were obtained at the baseline and 3 months, 1 year, and 2 years after RT. Imaging studies were assessed for pelvic fractures for up to 5 years. Patients with osteopenia, osteoporosis, or pelvic fractures at any point were referred to the endocrinology service for evaluation and treatment.

RESULTS

The median age at diagnosis was 51 years; 132 patients (56%) were menopausal. The primary diagnoses were cervical (63.6%), endometrial (30.5%), and vaginal cancer (5.9%). Sixteen patients (7.8%; 95% confidence interval, 4.5%-12.4%) had pelvic fractures with actuarial rates of 3.6%, 12.7%, and 15.7% at 1, 2, and 3 years, respectively. Fractures were associated with baseline osteoporosis (P < .001), higher baseline bone-specific alkaline phosphatase (P < .001), and older age (P = .007). The proportion of patients with osteopenia/osteoporosis increased from 50% at the baseline to 58%, 59%, and 70% at 3 months, 1 year, and 2 years, respectively.

CONCLUSIONS

A high proportion of women had significant decreases in BMD after pelvic RT, with 7.8% diagnosed with a pelvic fracture. BMD screening and pharmacologic intervention should be strongly considered for these high-risk women.

Sacral Fractures and Sacroplasty

Sacral fractures result from high-impact trauma or in the form of insufficiency or pathologic fractures, resulting from osteoporosis, radiation therapy, or malignancy. In the emergency setting, the escalating use of computed tomography has substantially increased diagnosis of sacral fractures, which are frequently occult on radiographs. Radiologists should be familiar with and create reports using the most current fracture classification systems, because this improves communication with the treatment team and optimizes patient care. Sacroplasty is a safe, minimally invasive treatment option for many types of sacral fractures. It provides rapid and durable pain relief, with a low incidence of complications.

Pathological fracture after radiotherapy: systematic review of literature

OBJECTIVE

To evaluate the epidemiological data and available treatments for fractures secondary to radiotherapy treatment.

METHODS

Identification of publications on pathological skeletal fractures previously exposed to ionizing radiation.

RESULTS

The incidence of fractures after irradiation varies from 1.2% to 25% with a consolidation rate of 33% to 75%, being more frequent in the ribs, pelvis, and femur. The time elapsed between irradiation and fracture occurs years after radiotherapy. Risk factors include age above 50 years, female gender, extensive periosteal detachment, circumferential irradiation, tumor size, and anterior thigh location. The etiology is still uncertain, but cellular disappearance, reduction of bone turnover and activity were observed hematopoietic as possible causes of failure of consolidation.

CONCLUSION

There is no consensus in the literature on the factors related to the development of fractures, with radiation dose, previous tumor size and periosteal detachment being suggested as potential factors.

Long-Term Endocrine and Metabolic Consequences of Cancer Treatment: A Systematic Review

The number of patients surviving ≥5 years after initial cancer diagnosis has significantly increased during the last decades due to considerable improvements in the treatment of many cancer entities. A negative consequence of this is that the emergence of long-term sequelae and endocrine disorders account for a high proportion of these. These late effects can occur decades after cancer treatment and affect up to 50% of childhood cancer survivors. Multiple predisposing factors for endocrine late effects have been identified, including radiation, sex, and age at the time of diagnosis. A systematic literature search has been conducted using the PubMed database to offer a detailed overview of the spectrum of late endocrine disorders following oncological treatment. Most data are based on late effects of treatment in former childhood cancer patients for whom specific guidelines and recommendations already exist, whereas current knowledge concerning late effects in adult-onset cancer survivors is much less clear. Endocrine sequelae of cancer therapy include functional alterations in hypothalamic-pituitary, thyroid, parathyroid, adrenal, and gonadal regulation as well as bone and metabolic complications. Surgery, radiotherapy, chemotherapy, and immunotherapy all contribute to these sequelae. Following irradiation, endocrine organs such as the thyroid are also at risk for subsequent malignancies. Although diagnosis and management of functional and neoplastic long-term consequences of cancer therapy are comparable to other causes of endocrine disorders, cancer survivors need individually structured follow-up care in specialized surveillance centers to improve care for this rapidly growing group of patients.

Increased risk of pelvic fracture after radiotherapy in rectal cancer survivors: A propensity matched study

To determine whether radiotherapy (RT) can increase pelvic fracture risk in rectal cancer survivors. Rectal cancer patients who underwent curative surgery between 1996 and 2011 in Taiwan were retrospectively studied using the National Health Insurance Research Database (NHIRD) of Taiwan. ICD‐9 Codes 808, 805.4‐805.7, 806.4‐806.7, and 820 (including pelvic, sacrum, lumbar, and femoral neck fracture) were defined as pelvic fracture. Propensity scores for RT, age, and sex were used to perform one‐to‐one matches between the RT and non‐RT group. Risks of pelvic and arm fractures were compared by multivariable Cox regression. Of the 32 689 patients, 7807 (23.9%) received RT, and 1616 suffered from a pelvic fracture (incidence rate: 1.17/100 person‐years). The median time to pelvic fracture was 2.47 years. After matching, 6952 patients each in the RT and non‐RT groups were analyzed. RT was associated with an increased risk of pelvic fractures in the multivariable Cox model (hazard ratio (HR): 1.246, 95% confidence interval (CI): 1.037‐1.495, P = 0.019) but not with arm fractures (HR: 1.013, 95% CI: 0.814‐1.259, P = 0.911). Subgroup analyses revealed that RT was associated with a higher pelvic fracture rate in women (HR: 1.431, 95% CI: 1.117‐1.834) but not in men, and the interaction between sex and RT was significant (P = 0.03). The HR of pelvic fracture increased 2‐4 years after RT (HR: 1.707, 95% CI: 1.150‐2.534, P = 0.008). An increased risk of pelvic fracture is noted in rectal cancer survivors, especially women, who receive RT.

Characterization of Insufficiency Fracture and Bone Metastasis After Radiotherapy in Patients With Cervical Cancer Detected by Bone Scan: Role of Magnetic Resonance Imaging

Background: Insufficiency fracture (IF) can show increased uptake on a bone scan (BS). IFs are often misinterpreted as bone metastases if the characteristic "Honda sign" (H-sign) is invisible. The purpose of the present study was to evaluate the utility of magnetic resonance imaging (MRI) alone for the characterization of IF and bone metastasis after radiotherapy in patients with cervical cancer detected by BS. Materials and Methods: Our study included 40 patients with cervical cancer after radiotherapy that showed pelvic emerging increased uptake on a BS during follow-up. Then further MRI examination was performed in all patients. Two radiologists independently reviewed the MR images, and the sensitivity, specificity and accuracy were calculated based on the mean scores. Diagnostic validity of the inter-observer was calculated by using kappa statistics. The gold standard was based on radiologic findings, clinical data and follow-up at least 12 months. Results: A total of 57 emerging bone lesions detected at BS were identified in the reference standard, including 43 IFs and 14 bone metastases. Only 20 patients showed a "H-sign" on the BS images. Using MRI analysis, all lesions detected by BS were found in MRI by both radiologists. On average, the sensitivity, specificity, and accuracy for distinguishing IFs from bone metastases were 95.3% (41/43), 92.8% (13/14), and 94.7% (54/57), respectively. The inter-observer variability was determined to be very good (kappa value = 0.962). Conclusions: MRI is a reliable diagnostic technique for the further characterization of emerging lesions detected by BS, MRI shows great diagnostic efficiency in the differentiation of IF and bone metastasis.

Delayed bone healing by collagen membrane in early phase of 4 weeks

OBJECTIVE

Barrier membranes are important in maintaining space in guided bone regeneration process by preventing downgrowth of epithelial or connective tissue. In this study, the effects of resorbable membranes during the early stages of bone regeneration in rats with impaired bone healing capacity were investigated.

STUDY DESIGN

Twenty-eight rats were selected for this study. Half of the animals were selected for radiation therapy before surgical procedure (G3, G4). Animals were assigned into 4 groups (G1-G4). A circular defect was created in the central parietal bone. It was covered with resorbable membrane in G2 and G4. After 4 weeks, the animals were sacrificed.

RESULTS

At week 4, the new bone formation was observed around the margin of old bone in G1, G2 and G4 groups. Osteoclast was most abundant in the G1 group (18.3 ± 7.7) and least abundant in the G4 group (7.9 ± 4.7). The mean of osteocalcin levels in blood was the highest in the G2 group and lowest in the G3 group. Only G4 group showed significant difference in Runx2 levels between before-treatment and after- treatment.

CONCLUSIONS

Bone healing is adversely affected after radiation therapy. In addition, resorbable membranes can delay healing in the early stages of bone regeneration.

Pharmacological interventions for the prevention of insufficiency fractures and avascular necrosis associated with pelvic radiotherapy in adults

BACKGROUND

Pelvic radiotherapy is a treatment delivered to an estimated 150,000 to 300,000 people annually across high-income countries. Fractures due to normal stresses on weakened bone due to radiotherapy are termed insufficiency fractures. Pelvic radiotherapy-related interruption of the blood supply to the hip is termed avascular necrosis and is another recognised complication. The reported incidences of insufficiency fractures are 2.7% to 89% and risk of developing avascular necrosis is 0.5%. These complications lead to significant morbidity in terms of pain, immobility and consequently risk of infections, pressure sores and mortality.

OBJECTIVES

To assess the effects of pharmacological interventions for preventing insufficiency fractures and avascular necrosis in adults over 18 years of age undergoing pelvic radiotherapy.

SEARCH METHODS

We performed electronic literature searches in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase and DARE to 19 April 2017. We also searched trial registries. Further relevant studies were identified through handsearching of citation lists of included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or non RCTs with concurrent comparison groups including quasi-RCTs, cluster RCTs, prospective cohort studies and case series of 30 or more participants were screened. We included studies assessing the effect of pharmacological interventions in adults over 18 years of age undergoing radical pelvic radiotherapy as part of anticancer treatment for a primary pelvic malignancy. We excluded studies involving radiotherapy for bone metastases. We assessed use of pharmacological interventions at any stage before or during pelvic radiotherapy. Interventions included calcium or vitamin D (or both) supplementation, bisphosphonates, selective oestrogen receptor modulators, hormone replacement therapy (oestrogen or testosterone), denosumab and calcitonin.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors to obtain missing data. Data were to be pooled using the random-effects model if study comparisons were similar, otherwise results were to be reported narratively.

MAIN RESULTS

We included two RCTs (1167 participants). The first RCT compared zoledronic acid with placebo in 96 men undergoing pelvic radiotherapy for non-metastatic prostate cancer.The second RCT had four treatment arms, two of which evaluated zoledronic acid plus adjuvant androgen suppression compared with androgen suppression only in 1071 men undergoing pelvic radiotherapy for non-metastatic prostate cancer.Both studies were at a moderate to high risk of bias and all evidence was judged to be of very low certainty.The studies provided no evidence on the primary outcomes of the review and provided limited data in relation to secondary outcomes, such that meta-analyses were not possible. Both studies focused on interventions to improve bone health in relation to androgen deprivation rather than radiation-related insufficiency fractures and avascular necrosis. Few fractures were described in each study and those described were not specific to insufficiency fractures secondary to radiotherapy. Both studies reported that zoledronic acid in addition to androgen deprivation and pelvic radiotherapy led to improvements in BMD; however, the changes in BMD were measured and reported differently. There was no available evidence regarding adverse effects.

AUTHORS' CONCLUSIONS

The evidence relating to interventions to prevent insufficiency fractures and avascular necrosis associated with pelvic radiotherapy in adults is of very low certainty. This review highlights the need for prospective clinical trials using interventions prior to and during radiotherapy to prevent radiation-related bone morbidity, insufficiency fractures and avascular necrosis. Future trials could involve prospective assessment of bone health including BMD and bone turnover markers prior to pelvic radiotherapy. The interventions for investigation could begin as radiotherapy commences and remain ongoing for 12 to 24 months. Bone turnover markers and BMD could be used as surrogate markers for bone health in addition to radiographic imaging to report on presence of insufficiency fractures and development of avascular necrosis. Clinical assessments and patient reported outcomes would help to identify any associated adverse effects of treatment and quality of life outcomes.

3D bone texture analysis as a potential predictor of radiation-induced insufficiency fractures

Background

The aim of our work is to assess the potential role of texture analysis (TA), applied to computed tomography (CT) simulation scans, in relation to the development of insufficiency fractures (IFs) in patients undergoing radiation therapy (RT) for pelvic malignancies.

Methods

We analyzed patients undergoing pelvic RT from Jan-2010 to Dec-2016, 31 of whom had developed IFs of the pelvis. We analyzed CT simulation scans using LifeX Software^©, and in particular we selected three regions of interest (ROI): L5 body, the sacrum and both the femoral heads. The ROI were automatically contoured using the treatment planning software Raystation^©. TA parameters included parameters from the gray-level histogram, indices from sphericity and from the matrix of GLCM (gray level co-occurrence matrix). The IFs patients were matched (1:1 ratio) with control patients who had not developed IFs, and were matched for age, sex, type of tumor, menopausal status, RT dose and use of chemotherapy. Univariate and multivariate analyses (logistic regression) were used for statistical analysis.

Results

Significant TA parameters on univariate analysis included both parameters from the histogram distribution, as well from the matrix of GLCM. On logistic regression analysis the significant parameters were L5-energy [P=0.033, odds ratio (OR): 1.997, 95% CI: 1.059-3.767] and FH-Skewness (P=0.014, OR: 2.338, 95% CI: 1.191-4.591), with a R2: 0.268. A ROC curve was generated from the binary logistic regression, and the AUC was 0.741 (95% CI: 0.627-0.855, P=0.001, S.E.: 0.058).

Conclusions

In our experience, 3D-bone CT TA can be used to stratify the risk of the patients to develop radiation-induced IFs. A prospective study will be conducted to validate these findings.

American Brachytherapy Task Group Report: A pooled analysis of clinical outcomes for high-dose-rate brachytherapy for cervical cancer

PURPOSE

Advanced imaging used in combination with brachytherapy (BT) has revolutionized the treatment of patients with cervical cancer. We present a comprehensive review of the literature for definitive radiation with high-dose-rate (HDR) BT. In addition, we investigate potential outcome improvement with image-based brachytherapy (IBBT) compared to studies using traditional Point A dosing. This review extensively investigates acute and late toxicities.

METHODS AND MATERIALS

This study reviews the literature from 2000 to 2015 with an emphasis on modern approaches including concurrent chemotherapy (chemoRT), radiation, and HDR BT and IBBT. Descriptive statistics and pelvic control (PC), disease-free survival (DFS), and overall survival (OS) outcomes were calculated using weighted means to report pooled analysis of outcomes.

RESULTS

Literature search yielded 16 prospective, 51 retrospective studies that reported survival outcomes, and 13 retrospective studies that focused on acute and late toxicity outcomes regardless of applicator type. There are 57 studies that report Point A dose specification with 33 having chemoRT, and 10 studies that use IBBT, 8 with chemoRT. Patients receiving radiation and chemoRT with HDR BT in the prospective studies, with >24 months followup, rates of PC were: for RT: 73%, SD: 11; CRT: 82%, SD: 8; DFS-RT: 55%, SD: 10; CRT: 65%, SD: 7; OS-RT: 66%, SD: 7; CRT: 70%, SD: 11. In the retrospective studies, the PC rates (weighted means) for the radiation and chemoradiation outcomes are 75% vs. 80%, and for DFS, the values were 55% vs. 63%, respectively. Comparing patients receiving chemoRT and IBBT to traditional Point A dose specification, there is a significant improvement in PC (p < 0.01) and DFS (p < 0.01) with IBBT. The range of genitourinary late toxicity reported for radiation was Grade 3: 1-6% and for chemoRT 2-20%. The range of late gastrointestinal toxicity for radiation was Grade 3: 4-11% and for chemoRT, 1-11%. For the late gynecologic toxicity, only 1 of the 16 prospective trials report a Grade 1-2 of 17% for radiation and 9% for chemoRT effects.

CONCLUSIONS

We present concise outcomes of PC, DFS, OS, and toxicity for cervical cancer patients treated with chemoradiation and HDR BT. Our data suggest an improvement in outcomes with the use of IBBT compared with traditional Point A dose prescriptions. In conclusion, HDR BT is a safe, effective modality when combined with IBBT.

Bone texture analysis using CT-simulation scans to individuate risk parameters for radiation-induced insufficiency fractures

This study deals with the role of texture analysis as a predictive factor of radiation-induced insufficiency fractures in patients undergoing pelvic radiation.

INTRODUCTION

This study aims to assess the texture analysis (TA) of computed tomography (CT) simulation scans as a predictive factor of insufficiency fractures (IFs) in patients with pelvic malignancies undergoing radiation therapy (RT).

METHODS

We performed an analysis of patients undergoing pelvic RT from January 2010 to December 2014, 24 of whom had developed pelvic bone IFs. We analyzed CT-simulation images using ImageJ macro software and selected two regions of interest (ROIs), which are L5 body and the femoral head. TA parameters included mean (m), standard deviation (SD), skewness (sk), kurtosis (k), entropy (e), and uniformity (u). The IFs patients were compared (1:2 ratio) with controlled patients who had not developed IFs and matched for sex, age, menopausal status, type of tumor, use of chemotherapy, and RT dose. A reliability test of intra- and inter-reader ROI TA reproducibility with the intra-class correlation coefficient (ICC) was performed. Univariate and multivariate analyses (logistic regression) were applied for TA parameters observed both in the IFs and the controlled groups.

RESULTS

Inter- and intra-reader ROI TA was highly reproducible (ICC > 0.90). Significant TA parameters on paired t test included L5 m (p = 0.001), SD (p = 0.002), k (p = 0.006), e (p = 0.004), and u (p = 0.015) and femoral head m (p < 0.001) and SD (p = 0.001), whereas on logistic regression analysis, L5 e (p = 0.003) and u (p = 0.010) and femoral head m (p = 0.027), SD (p = 0.015), and sex (p = 0.044).

CONCLUSIONS

In our experience, bone CT TA could be correlated to the risk of radiation-induced IFs. Studies on a large patient series and methodological refinements are warranted.

Pelvic insufficiency fracture (PIF) incidence in patients treated with intensity-modulated radiation therapy (IMRT) for gynaecological or anal cancer: single-institution experience and review of the literature

OBJECTIVE

To summarize the results of pelvic insufficiency fracture (PIF) incidence in patients with anal or gynaecological cancer treated by pelvic intensity-modulated radiation therapy (IMRT).

METHODS

The clinical and morphological (CT and/or pelvic MRI) characteristics of patients treated by IMRT at our institution between 2007 and 2014 were analyzed. The global incidence of PIF after external beam radiotherapy and the impact of tumour site (gynaecological or anal cancer) were determined. A dosimetric study was then performed to compare patients with and without pelvic fracture.

RESULTS

341 patients were treated by IMRT for gynaecological or anal cancer between 2007 and 2014. 15 patients experienced at least 1 pelvic fracture after external beam radiotherapy, corresponding to an overall incidence of 4.4%. Age and menopausal status were correlated with an increased fracture risk (p = 0.0274 and p < 0.0001, respectively). The site of the primary tumour (gynaecological or anal canal) was not associated with an excess fracture risk. The median maximum dose received at the fracture site was 50.3 Gy (range: 40.8-68.4 Gy).

CONCLUSION

The incidence of pelvic fracture after IMRT is low, but is higher after the age of 50 and in patients who are postmenopausal. Pre-treatment evaluation of bone density by bone densitometry and phosphorus-calcium assessment could be useful prior to the management of these patients. Advances in knowledge: Pelvic fractures are a frequent complication after radiotherapy. The influence of IMRT and clinical characteristics were evaluated in this study.

Walking Disability in Patients with Pelvic Insufficiency Fracture after Radiotherapy for Uterine Cervical Cancer

Objective

Radiotherapy is an essential component of curative or palliative therapy for patients with uterine cervical cancer. Although advances in radiotherapy have led to longer survival, survivors may consequently be at risk of pelvic insufficiency fracture (PIF). We retrospectively reviewed medical records and clinical outcomes to assess the impact of PIF on walking disability.

Methods

Between January 2002 and December 2009, 145 uterine cancer patients treated with radiotherapy in our hospital were reviewed. Among these, 15 patients (10.3%) were diagnosed with PIF. The types of fractures were identified according to the AO/OTA classification system. Medical records were examined to establish the time to first diagnosis of PIF, the type of fracture, and clinical outcomes. Disability was assessed using Barthel index mobility scores.

Results

The median time to PIF detection was 16 months. Of the 15 patients with PIF, 14 had type B fractures (7 cases of B2 and 7 cases of B3) and 1 had a type C fracture. Among 11 patients with pelvic pain, 6 achieved pain control but 5 patients with bilateral lesions in the posterior arch or lateral compression of the sacrum developed pain that finally resulted in walking disability and a lower performance status.

Conclusions

PIF causes severe motor disturbance in patients with unstable fracture types. Routine imaging checkups were useful during the 5 years after completion of radiotherapy; in nine patients the fracture progressed for longer than 1 year. In cancer rehabilitation for PIF patients, continuous assessment is essential for predicting walking disability.

Increased EZH2 and decreased osteoblastogenesis during local irradiation-induced bone loss in rats

Radiation therapy is commonly used to treat cancer patients but exhibits adverse effects, including insufficiency fractures and bone loss. Epigenetic regulation plays an important role in osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Here, we reported local bone changes after single-dose exposure to ¹³⁷C_S irradiation in rats. Femur bone mineral density (BMD) and trabecular bone volume in the tibia were significantly decreased at 12 weeks after irradiation. Micro-CT results showed that tBMD, Tb.h and Tb.N were also significantly reduced at 12 weeks after irradiation exposure. ALP-positive OB.S/BS was decreased by 42.3% at 2 weeks after irradiation and was decreased by 50.8% at 12 weeks after exposure. In contrast to the decreased expression of Runx2 and BMP2, we found EZH2 expression was significantly increased at 2 weeks after single-dose ¹³⁷C_S irradiation in BMSCs. Together, our results demonstrated that single-dose ¹³⁷C_S irradiation induces BMD loss and the deterioration of bone microarchitecture in the rat skeleton. Furthermore, EZH2 expression increased and osteoblastogenesis decreased after irradiation. The underlying mechanisms warrant further investigation.

Bone mineral density loss in thoracic and lumbar vertebrae following radiation for abdominal cancers

PURPOSE

To investigate the relationship between abdominal chemoradiation (CRT) for locally advanced cancers and bone mineral density (BMD) reduction in the vertebral spine.

MATERIALS AND METHODS

Data from 272 patients who underwent abdominal radiation therapy from January 1997 to May 2015 were retrospectively reviewed. Forty-two patients received computed tomography (CT) scans of the abdomen prior to initiation and at least twice after radiation therapy. Bone attenuation (in Hounsfield unit) (HU) measurements were collected for each vertebral level from T7 to L5 using sagittal CT images. Radiation point dose was obtained at each mid-vertebral body from the radiation treatment plan. Percent change in bone attenuation (Δ%HU) between baseline and post-radiation therapy were computed for each vertebral body. The Δ%HU was compared against radiation dose using Pearson's linear correlation.

RESULTS

Abdominal radiotherapy caused significant reduction in vertebral BMD as measured by HU. Patients who received only chemotherapy did not show changes in their BMD in this study. The Δ%HU was significantly correlated with the radiation point dose to the vertebral body (R=-0.472, P<0.001) within 4-8 months following RT. The same relationship persisted in subsequent follow up scans 9 months following RT (R=-0.578, P<0.001). Based on the result of linear regression, 5 Gy, 15 Gy, 25 Gy, 35 Gy, and 45 Gy caused 21.7%, 31.1%, 40.5%, 49.9%, and 59.3% decrease in HU following RT, respectively. Our generalized linear model showed that pre-RT HU had a positive effect (β=0.830) on determining post-RT HU, while number of months post RT (β=-0.213) and radiation point dose (β=-1.475) had a negative effect. A comparison of the predicted versus actual HU showed significant correlation (R=0.883, P<0.001) with the slope of the best linear fit=0.81. Our model's predicted HU were within ±20 HU of the actual value in 53% of cases, 70% of the predictions were within ±30 HU, 81% were within ±40 HU, and 90% were within ±50 HU of the actual post-RT HU. Four of 42 patients were found to have vertebral body compression fractures in the field of radiation.

CONCLUSIONS

Patients who receive abdominal chemoradiation develop significant BMD loss in the thoracic and lumbar vertebrae. Treatment-related BMD loss may contribute to the development of vertebral compression fractures. A predictive model for post-CRT BMD changes may inform bone protective strategies in patients planned for abdominal CRT.

[Insufficiency fractures after irradiation therapy - case series]

BACKGROUND

Radiation therapy plays an essential part in modern treatment regimes of musculoskeletal tumors. Nevertheless damage to the surrounding tissue does occur inevitably. Postradiogenic changes of bone are associated with decreased stability and an increased fracture rate. The orthopedic surgeon therefore faces a challenging situation with altered bone metabolism, changes in perfusion and soft tissue problems.

PATIENTS/MATERIAL AND METHODS

We present 3 cases of radiation induced fractures during the treatment of soft tissue tumors, all of which received radiation doses of > 58 Gy. All fractures occurred over 1 year after the exposure to radiation in otherwise uneventful follow ups.

RESULTS

Postoperative follow up showed fracture healing or in the case of the arthroplasty, osseous integration without further complications.

CONCLUSIONS

Radiation doses of ≥ 58 Gy are a major risk factor for pathological fractures in long bones. Regardless of their low incidence, fracture rates between 1,2 and 6,4 % prove their importance. Local tumor control has therefore to be weighed against the resulting decrease in bone quality and stability. Treatment options should always take into consideration the increased risk for complications such as infection, pseudarthroses and wound healing disorders. Our results show that substitution of vitamin D and calcium as well as the the use of reamed intramedullary implants benefits the outcome.

Fosså S, Trovik C, Lie SA. Pelvic irradiation does not increase the risk of hip replacement in patients with gynecological cancer. A cohort study based on 8,507 patients

BACKGROUND AND PURPOSE

Long-term survivors of cancer can develop adverse effects of the treatment. 60% of cancer patients survive for at least 5 years after diagnosis. Pelvic irradiation can cause bone damage in these long-term survivors, with increased risk of fracture and degeneration of the hip.

PATIENTS AND METHODS

Analyses were based on linkage between the Cancer Registry of Norway (CRN) and the Norwegian Arthroplasty Register (NAR). All women who had been exposed to radiation for curative radiotherapy of gynecological cancer (40-60 Gy for at least 28 days) were identified in the CRN. Radiotherapy had been given between 1998 and 2006 and only patients who were irradiated within 6 months of diagnosis were included. The control group contained women with breast cancer who had also undergone radiotherapy, but not to the pelvic area. Fine and Gray competing-risk analysis was used to calculate subhazard-rate ratios (subHRRs) and cumulative incidence functions (CIFs) for the risk of having a prosthesis accounting for differences in mortality.

RESULTS

Of 962 eligible patients with gynecological cancer, 26 (3%) had received a total hip replacement. In the control group without exposure, 253 (3%) of 7,545 patients with breast cancer had undergone total hip replacement. The 8-year CIF for receiving a total hip replacement was 2.7% (95% CI: 2.6-2.8) for gynecological cancer patients and 3.0% (95% CI: 2.95-3.03) for breast cancer patients; subHRR was 0.80 (95% CI: 0.53-1.22; p=0.3). In both groups, the most common reason for hip replacement was idiopathic osteoarthritis.

INTERPRETATION

We did not find any statistically significantly higher risk of undergoing total hip replacement in patients with gynecological cancer who had had pelvic radiotherapy than in women with breast cancer who had not had pelvic radiotherapy.

Postradiation Damage to the Pelvic Girdle in Cervical Cancer Patients: Is Intensity-Modulated Radiation Therapy Safer Than Conventional Radiation?

Objectives

Intensity-modulated radiation therapy (IMRT) is frequently utilized in the treatment of cervical cancer. Our study compared instances of pelvic fractures, osteonecrosis, and osteomyelitis posttreatment with conventional radiation therapy (RT) versus IMRT in patients with cervical carcinomas.

Methods

Eighty-three patients primarily treated with IMRT were case matched with 83 historical control subjects treated with conventional RT. Pretreatment and posttreatment computed tomography scans were reviewed. Logistic regression analysis was utilized to examine the effects of treatment type (conventional RT vs IMRT) on the occurrence of posttreatment pelvic bony structure complications while adjusting for confounders.

Results

In the IMRT group, 3 (4%) of 83 patients developed posttreatment sacral fractures (median follow-up, 51 months). In the conventional RT group, there were 14 pelvic girdle complications (17%): 9 fractures, 2 cases of osteonecrosis, and 3 cases of osteomyelitis (median follow-up, 43.5 months; odds ratio, 4.49 for conventional vs IMRT groups,P= 0.01; 95% confidence interval, 1.4–14.1). In addition, there were 4 cases of posttreatment osteoporosis in the conventional RT group. All patients with complications in the IMRT group and 11 of 13 in the conventional RT group were symptomatic.

Conclusions

Intensity-modulated radiation therapy is associated with a lower risk for pelvic girdle complications than conventional RT.

Clinical efficacy of alternating chemoradiotherapy by conformal radiotherapy combined with intracavitary brachytherapy for high-risk cervical cancer

OBJECTIVE

The purpose of this study was to assess the outcome of alternating chemoradiotherapy in patients with high-risk cervical cancer.

METHODS

We performed definitive alternating chemoradiotherapy in cervical cancer patients with at least one high-risk factor such as International Federation of Gynecology and Obstetrics III or IVA disease, primary tumor diameter ≥50 mm, positive pelvic node, and positive para-aortic node. Our chemoradiotherapy protocol was as follows: (i) alternating chemoradiotherapy with 5-fluorouracil and nedaplatin; (ii) whole pelvic radiotherapy with the dynamic conformal technique combined with intracavitary brachytherapy; (iii) prophylactic irradiation to the para-aortic region for International Federation of Gynecology and Obstetrics III/IVA or positive pelvic node and full-dose radiotherapy for positive para-aortic node. Between 1998 and 2010, 121 patients were treated with this protocol.

RESULTS

The median follow-up period was 53.7 months (7.6-162.2). International Federation of Gynecology and Obstetrics stages were IB; (9.1%), IIA; 6 (5.0%), IIB; 53 (43.8%), IIIA; 7 (5.8%), IIIB; 37 (30.6%) and IVA; 7 (5.8%), respectively. Nodal involvement was reported in 77 patients (63.6%) at the pelvis and 25 (20.7%) at the para-aortic region. The 5-year overall survival and progression-free survival rates were 80.0 and 63.4%, respectively. Regarding Grade ≥3 late toxicities, three patients developed urinary and three developed intestinal toxicities. We encountered no treatment-related death.

CONCLUSIONS

The clinical results of our alternating chemoradiotherapy protocol for high-risk cervical cancer are promising.

Raman spectroscopy demonstrates prolonged alteration of bone chemical composition following extremity localized irradiation

INTRODUCTION

Radiotherapy to the appendicular skeleton can cause an increased risk of developing catastrophic fractures with delayed bone healing or non-union, and may subsequently require multiple procedures and amputation. Biomechanical studies suggest that irradiated bone is more brittle, but the cause is unclear and cannot be explained by changes to bone structure or quantity, suggesting that there are crucial changes in irradiated bone material properties. Raman spectroscopy provides a means to assess the chemical properties of the mineral and matrix constituents of bone, which could help explain post-radiation embrittlement. In this study we use a murine tibial model with focal irradiation and perform Raman spectroscopy to test the hypothesis that changes in bone chemistry following irradiation is consistent with reduced bone quality and persists in the long term after irradiation.

METHODS

Female BALB/F mice aged 12weeks were subjected to unilateral, localized hindlimb irradiation in 4 daily 5Gy fractions (4×5Gy) totaling 20Gy, and were euthanized at 1, 4, 8, 12, and 26weeks post-irradiation (n=6/group). The irradiated (right) and non-irradiated contralateral control (left) tibiae were explanted and assessed by non-polarized and polarized Raman spectroscopy over the proximal cortical bone surface. Raman parameters used included the mineral/matrix ratio, mineral crystallinity, carbonate/phosphate ratio, collagen cross-link ratio, and depolarization ratio.

RESULTS

Significantly increased collagen cross-link ratio and decreased depolarization ratio of matrix were evident at 1week after irradiation and this persisted through 26weeks. A similar significant decrease was observed for depolarization ratio of mineral at all time points except 8 and 26weeks. At 4weeks after irradiation there was a significantly increased mineral/matrix ratio, increased mineral crystallinity, and decreased carbonate/phosphate ratio compared to controls. However, at 12weeks after irradiation these parameters had moved in the opposite direction, resulting in a significantly decreased mineral/matrix ratio, decreased crystallinity and increased carbonate/phosphate ratio compared to controls. At 26weeks, mineral/matrix, crystallinity and carbonate/phosphate ratios had returned to normal.

DISCUSSION

In this mouse model, Raman spectroscopy reports both bone mineral and collagen cross-link radiation-induced abnormalities that are evident as early as one week after irradiation and persists for 26weeks. The picture is one of extensive damage, after which there is an attempt at remodeling. We hypothesize that pathological cross-links formed by radiation damage to collagen are poorly resorbed during the altered remodeling process, so that new tissue is formed on a defective scaffold, resulting in increased bone brittleness.

Effect of different treatment plans on irradiated small-bowel volume in gynecologic patients undergoing whole-pelvic irradiation

To evaluate the effect of different treatment plans for whole-pelvic irradiation on small-bowel volumes (SBVs) in patients with gynecologic malignancies, 40 patients were enrolled in this study. Computed tomography (CT) simulations were performed, and the small bowel of each patient was outlined manually. Treatment plans with equal-weighted (EW) and non-equal-weighted (NEW) (70% in bilateral directions) techniques of four-field and intensity-modulated radiation therapy (IMRT) were performed. The V10-V100 represented the volume (cm³) at different levels of the prescribed doses (10-100%). The V10-V100 was compared among the different treatment planning techniques, and patients who were suitable for IMRT or NEW were identified. IMRT and NEW significantly reduced the V50-V100 and V40-V60 levels compared with EW, respectively. NEW caused a significant reduction in the V30-V60 levels in patients with a BMI ≥26 kg/m². Patients with IMRT demonstrated lower V70-V100 levels compared with those with NEW. In patients with a BMI ≥26 kg/m² or an age ≥55 years, lower V20-V50 levels were noted using NEW compared with IMRT. Treatment planning with larger weighting in the bilateral directions in four-field radiotherapy reduces the low-dose SBV in patients with gynecologic malignancies, especially in those with a high BMI or the elderly. IMRT effectively reduces high-dose SBV, especially in patients with a low BMI.

Zoledronic acid prevents loss of trabecular bone after focal irradiation in mice

Radiation therapy for soft tissue sarcomas and metastatic disease can adversely affect bone, leading to late-onset fragility fractures. Adjunct administration of bisphosphonates has been postulated as means of minimizing these adverse effects. Using a murine model of focal hindlimb irradiation, we examined the potential for zoledronic acid treatment to minimize the deleterious effects of localized radiotherapy (RTx) on bone. Mice received a single, unilateral hindlimb exposure of 20 Gy. Beginning 4 days prior to irradiation, and at 1, 2 and 3 weeks post-irradiation, animals were treated with zoledronic acid or saline/vehicle injections. Areal bone mineral density was assessed at 4 days, and 2, 4 and 12 weeks post-irradiation by dual-energy X-ray absorptiometry (DXA). Micro-computed tomography and axial compression testing were used to quantify changes in morphological and mechanical properties of femurs at 4 and 12 weeks post-irradiation. Radiation had differential effects on cortical and trabecular bone, increasing cortical bone mineral content (BMC), cortical bone volume (BV) and trabecular separation (Tb.Sp) while decreasing trabecular number (Tb.N) by 12 weeks after localized radiotherapy. Administration of zoledronic acid increased hindlimb areal bone mineral density in both the presence and absence of radiotherapy, increased cortical bone mineral content and bone volume, increased trabecular bone volume (BV/TV), increased trabecular number, increased trabecular thickness (Tb.Th), and decreased trabecular separation compared to irradiated and vehicle control femurs. Despite these improvements in morphology with zoledronic acid, no biomechanical advantage was observed. Further work is needed to define the role of bisphosphonates in prevention of post-irradiation fragility fractures.

N-acetylcysteine ameliorates γ-radiation-induced deterioration of bone quality in the rat femur

This animal study evaluated the radioprotective effects of N-acetylcysteine (NAC) and amifostine on the biomechanical properties of bone in Wistar albino rats of both genders. The rats were randomly divided into four groups of eight: a control group (C); a group given a single dose of 40 Gy of γ-irradiation (R); a group given γ-irradiation plus 200 mg/kg amifostine (R + amifostine); and a group given γ-irradiation plus 1000 mg/kg NAC (R + NAC). Extrinsic and intrinsic properties of bone, bone mineral density (BMD) and the cross-sectional area of the femoral shaft were determined. The cross-sectional area was significantly higher in the R + NAC and R + amifostine groups compared with the R and C groups. The BMD, maximum load and stiffness were also significantly higher in the R + NAC and R + amifostine groups than in the R group, and energy absorption capacity was higher in the R + NAC group than in the R group. These findings indicate that NAC and amifostine preserve bone quality in rats exposed to γ-irradiation.

Pelvic insufficiency fracture after radiotherapy in patients with cervical cancer in the era of PET/CT

PURPOSE

To determine the incidence, risk factors, and clinical characteristics of pelvic insufficiency fracture (PIF) in patients with cervical cancer.

MATERIALS AND METHODS

Between July 2004 and August 2009, 235 patients with non-metastatic cervical cancer were treated with definitive chemoradiation or postoperative radiotherapy. Among 235 patients, 117 (49.8%) underwent the first positron emission tomography/computed tomography (PET/CT) within 1 year after radiotherapy. The median radiation dose was 55 Gy (range, 45 to 60 Gy). Medical charts and imaging studies, including PET/CT, magnetic resonance imaging (MRI), CT, bone scintigraphy were reviewed to evaluate the patients with PIF.

RESULTS

Among 235 patients, 16 developed PIF. The 5-year detection rate of PIF was 9.5%. The 5-year detection rate of PIF in patients who underwent the first PET/CT within a year was 15.6%. The median time to development of PIF was 12.5 months (range, 5 to 30 months). The sites of fracture included 12 sacroiliac joints, 3 pubic rami, 3 iliac bones, and 1 femoral neck. Eleven of 16 patients having PIF complained of hip pain requiring medications. One patient required hospitalization for pain control. The significant risk factors of PIF were old age, body mass index less than 23, bone mineral density less than -3.5 SD, and the first PET/CT within a year after radiotherapy. Radiation dose and concurrent chemotherapy had no impact on PIF rate.

CONCLUSION

PIFs were not rare after pelvic radiotherapy in cervical cancer patients in the era of PET/CT. Timely diagnosis and management of PIF can improve quality of life in patients with cervical cancer, in addition to reducing unnecessary medical expenses.

Rapid loss of bone mass and strength in mice after abdominal irradiation

Localized irradiation is a common treatment modality for malignancies in the pelvic-abdominal cavity. We report here on the changes in bone mass and strength in mice 7-14 days after abdominal irradiation. Male C57BL/6 mice of 10-12 weeks of age were given a single-dose (0, 5, 10, 15 or 20 Gy) or fractionated (3 Gy × 2 per day × 7.5 days) X rays to the abdomen and monitored daily for up to 14 days. A decrease in the serum bone formation marker and ex vivo osteoblast differentiation was detected 7 days after a single dose of radiation, with little change in the serum bone resorption marker and ex vivo osteoclast formation. A single dose of radiation elicited a loss of bone mineral density (BMD) within 14 days of irradiation. The BMD loss was up to 4.1% in the whole skeleton, 7.3% in tibia, and 7.7% in the femur. Fractionated abdominal irradiation induced similar extents of BMD loss 10 days after the last fraction: 6.2% in the whole skeleton, 5.1% in tibia, and 13.8% in the femur. The loss of BMD was dependent on radiation dose and was more profound in the trabecula-rich regions of the long bones. Moreover, BMD loss in the total skeleton and the femurs progressed with time. Peak load and stiffness in the mid-shaft tibia from irradiated mice were 11.2-14.2% and 11.5-25.0% lower, respectively, than sham controls tested 7 days after a single-dose abdominal irradiation. Our data demonstrate that abdominal irradiation induces a rapid loss of BMD in the mouse skeleton. These effects are bone type- and region-specific but are independent of radiation fractionation. The radiation-induced abscopal damage to the skeleton is manifested by the deterioration of biomechanical properties of the affected bone.

Pelvic fractures after radiotherapy for cervical cancer: implications for survivors

BACKGROUND

The incidence of pelvic fractures and associated risk factors was determined in women treated with curative-intent radiotherapy for cervical cancer.

METHODS

The records of 516 women treated with curative-intent radiotherapy for cervical cancer between 2001 and 2006 at the University of Texas M. D. Anderson Cancer Center were reviewed. Among these, 300 patients had at least 1 post-treatment computed tomography scan or magnetic resonance imaging study available for review, and they comprised our study population. All imaging studies were re-reviewed by a single radiologist to evaluate for fractures.

RESULTS

Pelvic fractures were noted in 29 of 300 patients (9.7%). Fracture sites included sacrum (n = 24; 83%), sacrum and pubis (n = 3; 10%), iliac crest (n = 1; 3%), and sacrum and acetabulum (n = 1; 3%). Thirteen patients (45%) were symptomatic, with pain being the most common presenting symptom. The median time from the completion of radiotherapy to the detection of fractures on imaging studies was 14.1 months (range, 2.1-63.1 months), with 38% of patients diagnosed within 1 year and 83% diagnosed within 2 years of completing therapy. The median age of the patients at diagnosis was higher in the women who developed a fracture compared with the women who did not (56.5 years vs 46.7 years; P = .04). A higher number of women with a fracture were postmenopausal (62% vs 37%; P = .03). The median body mass index was lower in the women who had a fracture (26.0 kg/m2 vs 28.0 kg/m2; P = .03).

CONCLUSIONS

Pelvic fractures were detected in a substantial proportion of women after radiotherapy for cervical cancer. Bone mineral density screening and pharmacologic intervention should be considered in these women.

Risedronate prevents early radiation-induced osteoporosis in mice at multiple skeletal locations

INTRODUCTION

Irradiation of normal, non-malignant bone during cancer therapy can lead to atrophy and increased risk of fracture at several skeletal sites, particularly the hip. This bone loss has been largely attributed to damaged osteoblasts. Little attention has been given to increased bone resorption as a contributor to radiation-induced osteoporosis. Our aims were to identify if radiation increases bone resorption resulting in acute bone loss and if bone loss could be prevented by administering risedronate.

METHODS

Twenty-week-old female C57BL/6 mice were either: not irradiated and treated with placebo (NR+PL); whole-body irradiated with 2 Gy x-rays and treated with placebo (IR+PL); or irradiated and treated with risedronate (IR+RIS; 30 microg/kg every other day). Calcein injections were administered 7 and 2 days before sacrifice. Bones were collected 1, 2, and 3 weeks after exposure. MicroCT analysis was performed at 3 sites: proximal tibial metaphysis, distal femoral metaphysis, and the body of the 5th lumbar vertebra (L5). Osteoclasts were identified from TRAP-stained histological sections. Dynamic histomorphometry of cortical and trabecular bone was performed. Circulating TRAP5b and osteocalcin concentrations were quantified.

RESULTS

In animals receiving IR+PL, significant (P<0.05) reduction in trabecular volume fraction relative to non-irradiated controls was observed at all three skeletal sites and time points. Likewise, radiation-induced loss of connectivity and trabecular number relative to NR+PL were observed at all skeletal sites throughout the study. Bone loss primarily occurred during the first week post-exposure. Trabecular and endocortical bone formation was not reduced until week 2. Loss of bone volume was absent in animals receiving IR+RIS. Histology indicated greater osteoclast numbers at week 1 within IR+PL mice. Serum TRAP5b concentration was increased in IR+PL mice only at week 1 compared to NR+PL (P=0.05). Risedronate treatment prevented the radiation-induced increase in osteoclast number, surface, and TRAP5b.

CONCLUSIONS

This study demonstrated a rapid loss of trabecular bone at several skeletal sites after whole-body irradiation. Changes were accompanied by an increase in osteoclast number and serum markers of bone loss. Risedronate entirely prevented bone loss, providing further evidence that an increase in bone resorption likely caused this radiation-induced bone loss.

Insufficiency fractures after pelvic radiotherapy in patients with prostate cancer

PURPOSE

To assess the incidence, predisposing factors, and clinical characteristics of insufficiency fractures (IF) in patients with prostate cancer, who received pelvic radiotherapy as part of their definitive treatment.

METHODS AND MATERIALS

The charts of 134 prostate cancer patients, who were treated with pelvic radiotherapy between 1998 and 2007 were retrospectively reviewed. IF was diagnosed by bone scan and/or CT and/or MRI. The cumulative incidence of symptomatic IF was estimated by actuarial methods.

RESULTS

Eight patients were identified with symptomatic IF after a median follow-up period of 68 months (range, 12-116 months). The 5-year cumulative incidence of symptomatic IF was 6.8%. All patients presented with lower back pain. Insufficiency fracture developed at a median time of 20 months after the end of radiotherapy and was managed conservatively without any need for hospitalization. Three patients were thought to have metastatic disease because of increased uptake in their bone scans. However, subsequent CT and MR imaging revealed characteristic changes of IF, avoiding any further intervention. No predisposing factors for development of IF could be identified.

CONCLUSIONS

Pelvic IF is a rare complication of pelvic radiotherapy in prostate cancer. Knowledge of pelvic IF is essential to rule out metastatic disease and prevent unnecessary treatment, especially in a patient cohort with high-risk features for distant spread.

Sacral insufficiency fractures after preoperative chemoradiation for rectal cancer: incidence, risk factors, and clinical course

PURPOSE

Sacral insufficiency (SI) fractures can occur as a late side effect of pelvic radiation therapy. Our goal was to determine the incidence, risk factors, and clinical course of SI fractures in patients treated with preoperative chemoradiation for rectal cancer.

MATERIALS AND METHODS

Between 1989 and 2004, 562 patients with non-metastatic rectal adenocarcinoma were treated with preoperative chemoradiation followed by mesorectal excision. The median radiotherapy dose was 45 Gy. The hospital records and radiology reports of these patients were reviewed to identify those with pelvic fractures. Radiology images of patients with pelvic fractures were then reviewed to identify those with SI fractures.

RESULTS

Among the 562 patients, 15 had SI fractures. The 3-year actuarial rate of SI fractures was 3.1%. The median time to SI fractures was 17 months (range, 2-34 months). The risk of SI fractures was significantly higher in women compared to men (5.8% vs. 1.6%, p = 0.014), and in whites compared with non-whites (4% vs. 0%, p = 0.037). On multivariate analysis, gender independently predicted for the risk of SI fractures (hazard ratio, 3.25; p = 0.031). Documentation about the presence or absence of pain was available for 13 patients; of these 7 (54%) had symptoms requiring pain medications. The median duration of pain was 22 months. No patient required hospitalization or invasive intervention for pain control.

CONCLUSIONS

SI fractures were uncommon in patients treated with preoperative chemoradiation for rectal cancer. The risk of SI fractures was significantly higher in women. Most cases of SI fractures can be managed conservatively with pain medications.

Early increase in osteoclast number in mice after whole-body irradiation with 2 Gy X rays

Bone loss is a consequence of exposure to high-dose radiotherapy. While damage to bone vasculature and reduced proliferation of bone-forming osteoblasts has been implicated in this process, the effect of radiation on the number and activity of bone-resorbing osteoclasts has not been characterized. In this study, we exposed mice to a whole-body dose of 2 Gy of X rays to quantify the early effects of radiation on osteoclasts and bone structural properties. Female C57BL/6 mice (13 weeks old) were divided into two groups: irradiated and nonirradiated controls. Animals were killed humanely 3 days after radiation exposure. Analysis of serum chemistry revealed a 14% increase in the concentration of tartrate resistant acid phosphatase (TRAP)-5b, a marker of osteoclast activity, in irradiated mice (P < 0.05). Osteoclast number (+44%; P < 0.05) and osteoclast surface (+213%; P < 0.001) were elevated in TRAP-stained histological sections of tibial metaphyses. No significant change was observed in osteoblast surface or osteocalcin concentration or in trabecular microarchitecture (i.e. bone volume fraction) as measured through microcomputed tomography (P > 0.05). This study provides definitive, quantitative evidence of an early, radiation-induced increase in osteoclast activity and number. Osteoclastic bone resorption may represent a contributor to bone atrophy observed after therapeutic irradiation.

Pelvic bone complications after radiation therapy of uterine cervical cancer: evaluation with MRI

OBJECTIVE

The purpose of this study was to assess the prevalence and distribution of radiation-induced insufficiency fractures and to investigate other bony complications of the female pelvis associated with radiation therapy using MR images.

MATERIALS AND METHODS

Two radiologists retrospectively evaluated pelvic MR images of 510 patients (mean age, 54.7 years) who underwent pelvic irradiation for uterine cervical cancer for the presence and location of insufficiency fractures by consensus. We calculated the cumulative prevalence of pelvic insufficiency fractures on the basis of their results. In addition, we identified other associated bony complications of the female pelvis by reviewing the MR images.

RESULTS

Insufficiency fractures were diagnosed in 100 patients; the 5-year cumulative prevalence was 45.2%. An insufficiency fracture was diagnosed a median of 16.9 months after radiation therapy. The fracture sites were the sacrum body and alae, medial side of the iliac bone, the roof of the acetabulum, superior rami of the pubic bone, femoral heads, and L5 vertebra. Sixty-one patients (61%) developed multiple fractures, and among them, 40 (40%) had bilateral symmetric lesions of the sacral alae. Other complications associated with the radiation therapy, as determined by evaluation of the MR images, were osteolysis and avascular necrosis of the femoral head.

CONCLUSION

Radiation-induced pelvic insufficiency fractures are a frequent complication of radiation therapy for uterine cervical cancer. Osteolysis and avascular necrosis of the femoral head were also diagnosed using MRI after radiation therapy.

Bone architectural and structural properties after 56Fe26+ radiation-induced changes in body mass

High-energy, high-charge (HZE) radiation, including iron ions ((56)Fe(26+)), is a component of the space environment. We recently observed a profound loss of trabecular bone in mice after whole-body HZE irradiation. The goal of this study was to examine morphology in bones that were excluded from a (56)Fe(26+) beam used to irradiate the body. Using 10-week-old male Sprague-Dawley rats and excluding the hind limbs and pelvis, we irradiated animals with 0, 1, 2 and 4 Gy (56)Fe(26+) ions and killed them humanely after 9 months. Animals grew throughout the experiment. Trabecular bone volume, connectivity and thickness within the proximal tibiae were significantly lower than control in a dose-dependent manner. Irradiated animals generally had less body mass than controls, which largely accounted for the variability in bone parameters as determined by ANCOVA. Likewise, lower cortical parameters were associated with reduced mass. However, lesser trabecular thickness in the 4-Gy group could not be attributed to body mass alone. Indicators of bone metabolism were generally unchanged, suggesting stabilized turnover. Exposure to (56)Fe(26+) ions can alter trabecular microarchitecture in shielded bones. Reduced body mass seems to be correlated with these deficits of trabecular and cortical bone.